Now I want to say:
If the Toogle Button @setChecked(false) THEN Color = RED@
If the Toogle Button @setChecked(true) THEN Color = GREEN@

I tryed to implement a function:@void MainWindow::setFarbe_r() {
ui->pushButton->setStyleSheet("background-color:red;");@
and the Connect:
@connect(ui->pushButton, SIGNAL(clicked()), this, SLOT(setFarbe_r()));@
but it doesnt work.

What I also could imagine that under the button would be displayed a textline.
For example when the button is pressed -> text: "button is pressed"

Hello zhekka777,
Why don't u use "toggled slot of QPushButton "provided by Qt in order to behave as a toggle button..I have used it to make a toggle button .
First drag and drop a QPushButton on MainWindow and set it's property "checkable" to true and go to slot of QPushButton choose signal toggled(bool).
Write the following snippet of code inside this slot.
void MainWindow::on_pushButton_toggled(bool checked)
{